Investments in Unconsolidated Entities (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Impairment of real estate	$ 235,000	$ 1,100,000	$ 5,070,000	$ 1,100,000
Total Impairment of investment in unconsolidated entities	0	2,282,000	0	14,438,000
Impairment of unconsolidated entities	0	2,282,000	0	15,181,000
Mixed-Use Land Development [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Company's portion of impairment of real estate	0	0	0	743,000
Mixed-Use Land Development [Member] | Mercy Campus at Central Station [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Total Impairment of investment in unconsolidated entities	0	1,817,000	0	1,817,000
Impairment of unconsolidated entities	0	1,817,000	0	1,817,000
Mixed-Use Land Development [Member] | Old Stone Crossing at Caldwell Creek [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Impairment of real estate	0		0	1,457,000
Impairment of unconsolidated entities	0		0	743,000
Office Buildings [Member] | 818 Mission Street [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Total Impairment of investment in unconsolidated entities	0		0	4,018,000
Impairment of unconsolidated entities	0		0	4,018,000
Office Buildings [Member] | Bulletin Building [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Total Impairment of investment in unconsolidated entities	0		0	3,543,000
Impairment of unconsolidated entities	0		0	3,543,000
Specialty Retail Centers [Member] | Metreon [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Total Impairment of investment in unconsolidated entities	0		0	4,595,000
Impairment of unconsolidated entities	0		0	4,595,000
Other [Member]
Summary of Impairment of Real Estate Investments in Unconsolidated Entities
Impairment of real estate	235,000	0	235,000	0
Total Impairment of investment in unconsolidated entities	0	465,000	0	465,000
Impairment of unconsolidated entities	$ 0	$ 465,000	$ 0	$ 465,000